New evidence our neighborhood in space is stuffed with hydrogen

Only the two Voyager spacecraft have ever been there, and it took than more than 30 years of supersonic travel. It lies well past the orbit of Pluto, through the rocky Kuiper belt, and on for four times that distance. This ...

New analysis of black hole reveals a wobbling shadow

In 2019, the Event Horizon Telescope Collaboration delivered the first image of a black hole, revealing M87*—the supermassive object in the center of the M87 galaxy. The team has now used the lessons learned last year to ...

For many families, the first disaster can be far from the last

Sasha Smith was out of work and battling throat cancer when, on Aug. 29, 2005, the floodwaters of Hurricane Katrina began to lap against her home in Orleans Parish. The young mother clutched her 2-year-old son Alex and fled ...

Explaining glaciers of solid methane and nitrogen on Pluto

Planetary scientist Dr. Helen Maynard-Casely and associates have reported for the first time how solid methane and nitrogen expand in response to temperature changes and resolved an historic ambiguity relating to the structure ...

Subaru Telescope and New Horizons explore the outer solar system

Collaborative observations with NASA's New Horizons mission have been ongoing at the Subaru Telescope since May 2020. Hyper Suprime-Cam (HSC), the wide field camera mounted on the prime focus of the Subaru Telescope, is used ...

10 cool things we learned about Pluto from New Horizons

Five years ago today, NASA's New Horizons spacecraft made history. After a voyage of nearly 10 years and more than 3 billion miles, the intrepid piano-sized probe flew within 7,800 miles of Pluto. For the first time ever, ...

New lessons from the worst oil spill disaster ever

Ten years ago, the Deepwater Horizon accident in the Gulf of Mexico killed eleven men and resulted in the largest accidental oil spill in history. Years of investigations concluded that the drilling crew missed critical warning ...

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Horizon

The horizon (or skyline) is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting intersection of earth and sky is called the visible horizon. When looking at a sea from a shore, the part of the sea closest to the horizon is called the offing. The word horizon derives from the Greek "ὁρίζων κύκλος" (horizōn kyklos), "separating circle", from the verb "ὁρίζω" (horizō), "to divide, to separate", and that from "ὅρος" (oros), "boundary, landmark".

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